The two most common bunker problems are allowing your club to hit the ball instead of using the sand as a cushion and allowing your spine or stance to tilt back which causes the club to enter the sand too early
Do not approach your chipping stance like a full swing stance, keep your feet close together, slightly open, weight on your front leg and shoulders square to the target, this set up clears your hips prior to the shot and puts more of the toe of the club flat on the ground
Learn how to read the contour of the green, the grain and the terrain around the green